The roasted lamb in this recipe is paired with a plum jam sauce, rather than the customary mint jelly.
Prepare Roasted Lamb: Preheat oven to 325 degrees F. Rub leg of lamb all over with cut sides of garlic. In a small bowl, combine parsley, celery salt, pepper and paprika. Sprinkle parsley mixture evenly over lamb; rub in with your fingers. Place the lamb, fat side up, on a rack in a shallow roasting pan. Insert an oven-going meat thermometer in the center, making sure bulb does not touch bone. Roast, uncovered, for 1 1/4 hours.
Meanwhile, in a small saucepan, melt butter over medium heat. Add carrot and onion; cook 3 to 4 minutes or until vegetables are tender. Stir in bread crumbs. Remove lamb from oven. Carefully pat crumb mixture over top of lamb. Continue roasting for 45 minutes to 1 hour or until desired doneness (140 degrees F for medium-rare or 155 degrees F for medium). Cover with foil; let stand for 10 minutes before slicing. (The temperature of the meat will rise about 5 degrees F during standing.)
Meanwhile, prepare Plum Jam Sauce: In a medium saucepan, whisk together plum jam, pineapple juice, orange juice, flour, dry mustard and mace. Cook and stir until thickened and bubbly. Cook and stir for 2 minutes more.
Serve lamb with warm or cooled Plum Jam Sauce. If desired, garnish with fresh plum wedges.
5 lean protein, 1 1/2 other carbohydrate, 1 fat